/Engine/Source/Developer/AssetTools/Public/AdvancedCopyCustomization.h
Allows for additional validation of the packages to be copied and their destination. Returns false if anything doesn't pass validation
virtual bool CustomCopyValidate ( const [TMap](API\Runtime\Core\Containers\TMap)< [FString](API\Runtime\Core\Containers\FString), [FString](API\Runtime\Core\Containers\FString) > & OutPackagesAndDestinations ) const